I believe many of the stones released in liver flushes are definetely pre-present and real, (Ive done 30 or so liver flushes myself) but there are reactions that can occur in people's body which can form the stone-like formations of bile as well through doing a flush. There is no other apparent explanation for the sheer amount of stones some people flush out regularly with flushes unending unless their gallbladder/livers are forming hundreds of new stones every week.